CCS/TMS320F28335: How can I measure the elapsed time between each loop?

Ata Khiabani

Part Number: TMS320F28335

Tool/software: Code Composer Studio

Hello

I am trying to measure the elapsed time between each time running the code. I looked at example "CpuTimer" but I don't know if I can do it with this example because I don't want to have interrupts I just want to measure the elapsed time. How should I measure it?

Best,

Ata

over 8 years ago

0 Ki over 8 years ago

TI__Guru**** 472351 points

Hi Ata,
Use the profile clock to count cycles:
processors.wiki.ti.com/.../Profile_clock_in_CCS

Then use the below formula to covert to time:
processors.wiki.ti.com/.../Profile_clock_in_CCS

Thanks
ki

0 Ata Khiabani over 8 years ago in reply to Ki

Intellectual 780 points

Thank you Ki. However I want to use this elapsed time in my code, so I need to incorporate it in my code.
for example at first "t=0", then one cycle later it will be "1 micro-seconds". I want to be able to use this time in my code. Can I do it?

0 Ki over 8 years ago in reply to Ata Khiabani

TI__Guru**** 472351 points

Are you using TI-RTOS with your application?

0 Ata Khiabani over 8 years ago in reply to Ki

Intellectual 780 points

No, I don't know what it is and how I should use it. Can you tell me what is the purpose of it? Does it have built-in functions?

0 Ata Khiabani over 8 years ago in reply to Ata Khiabani

Intellectual 780 points

I was browsing the forum, and I saw a post that said it is possible to do it with eCAP. Can you tell me how I should do it? or is there an example file to show it?

0 Ki over 8 years ago in reply to Ata Khiabani

TI__Guru**** 472351 points

Ata Khiabani said:
No, I don't know what it is and how I should use it. Can you tell me what is the purpose of it? Does it have built-in functions?

TI-RTOS is TI's real-time embedded operating system. It has functions for instrumentation such as what you are looking for

http://processors.wiki.ti.com/index.php/TI-RTOS

Obviously if you are not using it already, then you would not start using it just for profiling.

0 Ki over 8 years ago in reply to Ata Khiabani

TI__Guru**** 472351 points

Ata Khiabani said:
I was browsing the forum, and I saw a post that said it is possible to do it with eCAP. Can you tell me how I should do it? or is there an example file to show it?

It is best to ask inside the C2000 forum:

https://e2e.ti.com/support/microcontrollers/c2000/f/171

The experts there can help you best

0 programmable solution over 8 years ago in reply to Ki

Expert 1500 points

You can set and clear a GPIO bit and measure the elapsed time with an oscilloscope.
GpioDataRegs.GPACLEAR.bit.GPIO11 = 1;
GpioDataRegs.GPASET.bit.GPIO11 = 1;

0 Ata Khiabani over 8 years ago in reply to programmable solution

Intellectual 780 points

Thank you but as I said I need this time in my code. Each loop in the code I need to use the updated "elapsed time".

0 Keith Barkley over 8 years ago in reply to Ata Khiabani

Guru 42215 points

What kind of resolution do you need?

I suggest doing an arduinoism and creating a "millis()" functionality. Create a long unsigned variable and set up a timer interrupt that will cause it to be incremented every millisecond.

Each time through the loop, you simply note the value of this variable to know the number of milliseconds that have elapsed. If you use subtraction, you don't even need to worry about rollover.

If you need better resolution, you can increment every 100 uS or whatever.

If you are using DriverLib/Simpllink check out the SysTick module.

0 Ata Khiabani over 8 years ago in reply to Keith Barkley

Intellectual 780 points

Thank you for the suggestion.
I want to be able to do switching every 20 uS, so the resolution is minimum 20 uS. Is it possible to increment it every microsecond? I think if I am able to do it, it will hopefully solve the problem.

0 programmable solution over 8 years ago in reply to Ata Khiabani

Expert 1500 points

Hi,

There are some code examples of eCAP towards the end of this document.

http://www.ti.com/lit/ug/sprufg4a/sprufg4a.pdf

0 Keith Barkley over 8 years ago in reply to Ata Khiabani

Guru 42215 points

Depends on your clockspeed, micros() on the arduino increments every 4 uS.

0 Ata Khiabani over 8 years ago in reply to Keith Barkley

Intellectual 780 points

In TMS320F28335, isn't the clock speed 150 MHz? So Shouldn't it be able to do it?

0 Ki over 8 years ago in reply to Ata Khiabani

TI__Guru**** 472351 points

Moving this thread to C2000 forum

0 Devin Cottier over 8 years ago in reply to Ki

TI__Guru 60865 points

Hi Ata,

If you want to do some task every 20us, why not just setup a CPU timer or ePWM timer to generate an interrupt exactly every 20us?

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CCS/TMS320F28335: How can I measure the elapsed time between each loop?